Plain clothes include a couple of accessories lacking finish (5)

I believe the answer is:

mufti

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'plain clothes' is the definition.
(I've seen this in another clue)

I can't explain the rest of the clue.

(Other definitions for mufti that I've seen before include "Civilian dress, in army terms" , "Soldier's civilian clothes" , "Ordinary clothes" , "officer of the law" , "For soldiers, civilian dress" .)

I've seen this clue in The Guardian.

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